INCOMING CALLS KILL MODEM

I have been going round and round with tech support for over a month. We are a radio station and use DSL to get the studio audio to the transmitter. We installed the DSL without any attached telephones. We found that several times a day the DSl would fail, taking us off the air. On a hunch we tried calling the phone number attched to the DSL even though no phone is connected. Surprise! When we would dial the number and hear the first ring the modem would drop out and the dsl order light would start flashing. the carrier would come back after about a minute. Tech support has no answer. We are 18,000 feet from central office but another DSl line coming in on the same cable is not disrupted if the associated number is called. We have been getting nothing but talk for weeks from tech support. Theyy always claim its being elevated and someone will call noone ever calls.. anybody got any ideas?